Salad oils and method of making them



Patented Nov. 21, 1967 3,353,967 SALAD OILS AND METHOD OF MAKING THEMEdwin S. Lutton, Cincinnati, Ohio, assignor to The Procter & GambleCompany, Cincinnati, Ohio, a corporation of Ohio No Drawing. Filed Mar.27, 1964, Ser. No. 355,486

9'Claims. (Cl. 99-163) -ABSTRACT OF THE DISCLOSURE Salad oil containing,as an inhibitor of solids deposition, 0.00l1% polysaccharide (215saccharide units per molecule) at least one-half esterified with -6unsaturated fatty acid dimer and C -C saturated fatty acid, said aciddimer and acid being in a ratio of 1:6 to 6:1.

This invention relates to improved salad oils and to a method forimproving salad oils.

Oils which are suitable for salad use frequently are stored inrefrigerators. The prolonged cooling of such oils to temperaturesnormally encountered in refrigerators, such as from about 40 .F. .toabout 50 F., generally results in the deposition of crystallinematerial, usually solid triglycerides, from the oil. This material mayappear in the form of a cloud, or as clusters of crystals, and isconsidered objectionable by the housewife. In general, the tendencytoform solid glycerides in oils also adversely affects the suitability ofthe oil for use in mayonnaise emulsions. Mayonnaise emulsions preparedfrom such oils tend to be unstable at low temperatures and are moreeasilybroken.

Frequently it is desirable to hydrogenate natural vegetable oils, suchas soybean oil, in order to improve their oxidative stability; however,hydrogenation tends to produce oil components of decreased solubility atordinary refrigeration temperatures.

' Accordingly, the. primary object of this invention is to provide asalad oil of improved resistance to solids precipitation at coldtemperatures.

It has now been found according to the present invention that thestorage time at low temperatures without clouding can be greatlyextended for a given salad oil by dissolving therein from about 0.001%to about 1%, by weight, of a mixed polysaccharide ester of oleic aciddimer and palmitic acid, said polysaccharide having from 2 to about 15saccharide units per molecule. The polysaccharide should be at leastabout one-half-esterified,

and the ratio of oleic acid dimer to palmitic acid in the esterpreferably should be from about 1:6 to about 6:1. The esters can beprepared by simple esterification reactions-well known to those skilledin the art by elimi nation of water in a reaction between a ca-rboxycompound and a hydroxy compound. A preferred method which includes anintermediate methanolysis step is illustrated in the examples below.-

The polysaccharides which can be used to form suitable esters in thepractice of this invention include, by way of example and notlimitation: disaccharides such as sucrose, maltose, lactose, andmelibiose; trisaccharides such as mannotriose and rafiinose;tetrasaccharides such as stachyose;dextrins having from about 5 to about15 saccharide units per molecule; and mixtures of the foregoingpolysaccharides. These polysaccharides can be obtained from well-knownsources such as those described in the co-pending application ofFrederick R. Hugenberg and Edwin S. Lutton, U.S. Ser. No. 355,424.

In the mixed polysaccharide esters of this invention, the palmitic acidcan be replaced with other long-chain saturated fatty acids and theoleic acid dimer can be replaced with other long-chain unsaturated fattyacid dimers with substantially equivalent results. For example, thelong-chain fatty acids which can be used also include myristic, stearicand other long-chain, aliphatic, monobasic acids having from about 14 toabout 22 carbon atoms such as those described in the co-pendingapplication of Frederick R. Hugenberg and Edwin S. Lutton, U.S. Ser. No.355,424.

The fatty acid dimers which can be used in the practice ofthis inventionare long-chain, aliphatic, dibasic acids having from about 28 to about44 carbon atoms in the molecule. They are generally obtained fromunsaturated fatty acids having from about 14 to about 22 carbon atomswhich can be polymerized to form dimers. For example, linoleic acid canbe polymerized by heating to form linoleic acid dimer as follows:

Common examples of such polymerizable acids are those containing two ormore double bonds (polyunsaturated acids) such as the octadecadienoicacids containing two double bonds, for example, the above-mentionedlinoleic acid, and the octadecatrienoic acids containing 3 double bonds,for example, linolenic and eleostearic acids. Other common polymerizablepolyunsaturated acids having from about 14 to about 22 carbon atomswhich can be used in the practice of this invention are octadecatrienoicacid (e.g., licanic acid), octadectetraenoic acid (e.g., parinaricacid),eicosadienoic acid, eicostetraenoic acid (e.g., arachidonic acid),5,13-docosadienoic acid,- and clupanodonic acid. Monounsaturated fattyacids, such as oleic, elaidic and erucic acids also can be used to formsuitable long-chain fatty acid dimers which can be used in the practiceof this invention.

As an example, an ideal starting material for the preparation oflinoleic acid dimer is pure linoleic acid. It will be appreciated,however, that theacids employed occur in nature as complex mixtures andisolation of pure linoleic acid is, as a practical matter, commerciallyunfeasible. Instead, sources rich in linoleic acid (generally 30% to areemployed as starting acids.

readily polymerizable by conventional means is by reference to theiodine value (I.V.), i.e., the number of grams of iodine equivalent tothe halogen absorbed by a.

gram sample.- In general, acid mixtures having iodine values of at leastwill have sufiicient ,double bond functionality to readily form thepreferred long-chain fatty acid dimers by conventional means.

Illustrative of natural sources which are rich in linoleicacid aresoybean oil, cottonseed oil, peanut oil, corn oil, sesame seed oil,sunflower seed oil, saffiower oil, linseed oil and perrilla oil.Oiticica oil is a particularly good source of licanic acid and tung oilcontains a high concentration of eleostearic acid. Fishoils, such asherring, manhaden, pilchard, salmon, and sardine oil also are suitablesources of polymerizable acids, particularly the higher fatty acids suchas arachidonic and clupanodonic acids. Other oils such as tall oil,dehydrated castor oil, olive oil and rapeseed oil also containsignificant proportions of suitable unsaturated acids. For example,olive oil is rich in oleic acid and rapeseed oil is rich in erucic acid.

The long-chain fatty acid dimers of this invention can be prepared byvarious methods known to those skilled in the art. For example, fattyoils containing substantial amounts of glycerides of the above-mentionedpolyunsaturated acids can be polymerized by thermal treatment. Theprocess is accelerated by the presence of polymerization catalysts. Thepolymeric glycerides thus formed can be converted to the polymericacids, for example, by hydrolysis.

Another method for the preparation of long-chain fatty acid dimerscomprises subjecting the fatty oils to alcoholysis wit-h monohydricalcohols such as methanol and ethanol, thereby converting the glyceridesof the unsaturated acids to the corresponding mouoesters. The monoesterscan be polymerized as above to yield esters of polymeric acid, fromwhich the free polymeric acids can be obtained by hydrolysis.

Still another method for the preparation of long-chain fatty acid dimerscomprises producing the free unsaturated fatty acids by hydrolysis ofthe fatty oils, followed by polymerization of the acids.

In the course of any of the above methods of preparation, the polymericacids can be further purified or fractionated by any suitable means suchas by distillation, crystallization or solvent extraction.

A preferred method of polymerizing the unsaturated fatty acids to formlong-chain fatty acid dimers is described in US. Patent 2,482,761,granted to Goebel, Sept. 27, 1949, and comprises heating apolyunsaturated fatty acid at an elevated pressure and a polymerizingtemperature of at least about 260 C. in the presence of a small amountof water.

Suitable methods for the polymerizing of monounsaturated fatty acids toform long-chain fatty acid dimers are described in US Patent 2,731,481,granted to Harrison et al., Jan. 17, 1956, and US. Patent 2,793,219,granted to Barrett et al., May 21, 1957.

It Will be appreciated that the polymerization methods generallyemployed will produce some trimer as well as the desired dimer. Forexample, a typical commercially available long-chain fatty acid dimerprepared from oleic or linoleic acid will contain from about 70% to 90%dimer, from about to trimer, and even traces of monobasic oleic orlinoleic acid from which the dimer is derived. It should be understoodthat such mixtures or mixtures containing even higher proportions oftrimer can be used in the practice of this invention.

The mixed polysaccharide esters of this invention also can contain aportion of short-chain fatty acid radicals, such as acetic and propionicfatty acid radicals, and a portion of long-chain unsaturated fatty acidradicals, such as oleic and linoleic fatty acid radicals, such as thosedescribed in the co-pending application of Frederick R. Hugenberg andEdwin S. Lutton, U.S. Ser. No. 355,424, provided that theherein-described proportions of longchain saturated fatty acids andlong-chain unsaturated fatty acid dimers are also used to esterify thepolysaccha ride.

A wide variety of oils can be used as base oils which can be maderesistant to deposition of high-melting solids at low temperatures inaccordance with this invention. Included among suitable oils are theso-called natural salad oils such as olive oil, sunflower seed oil,safflower oil and sesame seed oil. Oils such as cottonseed oil and cornoil preferably are given a preliminary Winterizing, de-

waxing, or similar other treatment to remove the highermelting solids toform a good base salad oil. Other oils, such as soybean oil, may requiresome hydrogenation to improve resistance to oxidative deterioration withprolonged storage, and the higher-melting glycerides formed during thishydrogenation treatment preferably are removed by winterization. Basesalad oils can also be formed by directed, low-temperatureinteresterification or rearrangement of animal or vegetable fattymaterial, followed by removal of higher-melting glycerides formed duringthe reaction. See, for example, US. Patent 2,442,- 532, granted to E. W.Eckey, June 1, 1948. Another group of oils includes those in which oneor more short chain or lower fatty acids having from 2 to about 6 carbonatoms, such as acetic and propionic acids, replace in part,

the longer chain or higher fatty acids present in natural triglycerideoils. Other base salad oils will suggest themselves to those skilled inthe art, provided they have a suitable chill test as hereinafterdefined. The base salad oils can be used individually or as mixtures ofoils. As used herein, the term base salad oil is intended to include anysalad oil which will not form solids immediately when cooled to 30 F.

The procedure for measuring the resistance of salad oils to clouding andthe crystal inhibiting activity of the esters as used hereinafterinvolves preheating the oil or oil with inhibitor to a temperature ofabout 140 F.. then cooling a 100 gram sample with air having atemperature of about 30 F. until solids form in the oil or oil withinhibitor. As used herein, the term chill test is intended to define thetotal length of time of cooling with air having a temperature of 30 F.until such solids form.

The ester and the base salad oil can be mixed together in any convenientmanner. For example, ester in liquid form can be mixed with the oil. Ifthe ester is in solid form, it can be dissolved in the oil, although itmay be desirable to heat the oil or the mixture of the oil and ester tofacilitate solution.

The following examples will serve to further illustrate the invention.However, it should be understood that the invention is not limited tothese illustrative examples.

Example 1 Commercial oleic acid dimer (Empol 1018) (500 grams) isrefluxed with methanol (1000 cubic centimeters) for 2 hours usingsulfuric acid catalyst (10 grams) to form the methyl ester of oleic aciddimer. The crude methyl ester is washed with 5% K CO solution and withwater and then dried under vacuum. Sucrose '(11 grams) is heated withdimethylformamide (100 cc.) to 60 C. to homogeneity. The above methylester of oleic acid dimer (43 grams), Triton B-40% benzyltrimethylarnmonium hydroxide in methanol 10 cubic centimeters), andcyclohexane (100 cubic centimeters) are added to the sucrose anddimethylformamide mixture, and the methyl alcohol is driven otf over aperiod of 3 to 4 hours at C. to 120 C. The above-formed sucrose ester ofoleic acid dimer (30 grams) is refluxed with palmitoyl chloride(30-grarns) in the presence of cyclohexane cubic centimeters) andpyridine (10 cubic centimeters) for about one hour to form a mixedsucrose ester of oleic acid dimer and palmitic acid (sucrose completelyesterified with oleic acid dimer and palmitic acid in 1:1 ratio). Themixed sucrose ester at a concentration of 0.1%, by weight, in winterizedcottonseed oil (having a chill test of 12 hours) extends the chill testof the winterized cottonseed oil to greater than 50 hours.

Example 1 is repeated except that: in Example 2 partially hydrogenatedand winterized soybean oil (Iodine Value l07)-is substituted forwinterized cottonseed oil in an equal amount; in Example 3 raffinose issubstituted for sucrose in an equivalent amount; in Example 4 stearoylchloride is substituted for palmitoyl chloride in an equivalent amount;in Example 5 linolenic acid dimer containing about 25% trimer issubstituted for oleic acid dimer in an equivalent amount; in Example 6one-fourth of the palmitoyl chloride is replaced with an equivalentamount of oleoyl chloride and another one-fourth is replaced with anequivalent amount of acetyl chloride; 'in Example 7 the ratio of oleicacid dimer to palmitic acid in the mixed ester is changed to 1:3; inExample 8 the ratio of oleic acid dimer to palmitic acid in the mixedester is changed to 3:1; and, in Example 9 the concentration of themixed ester is changed to 0.05%. In these Examples 2 through 9, theimprovements in chill test results obtained with the mixed esters aresubstantially equivalent to the results obtained in Example 1.

If too large an amount of inhibitor is present in the salad oil, it willbe precipitated out of the oil as the oil-inhibitor mixture is cooledand possibly even promote crystallization of high-melting solids in theoil. Too small an amount of inhibitor, of course, will be relativelyineffective. Amounts of ester in excess of 1%, by weight, areunnecessary as affording no significant added improvement of the oil;and it is preferred to use from about 0.05% to about 0.1%.

What is claimed is:

1. A clear glyceride salad oil having improved resistance to depositionof high-melting solids and comprising a base salad oil having dissolvedtherein from about 0.001% to about 1%, by weight, of a mixedpolysaccharide ester of oleic acid dimer and palmitic acid, saidpolysaccharide having from 2 to about 15 saccharide units per moleculeand being at least one-half esterified, and said oleic acid dimer andpalmitic acid being in a ratio of from about 1:6 to about 6:1.

2. The clear glyceride salad oil of claim 1 in which the polysaccharideis sucrose.

3. The clear glyceride salad oil of claim 1 in which the polysaccharideis raffinose.

4. The clear glyceride salad oil of claim 1 in which the base salad oilis derived from cottonseed oil.

5. The clear glyceride salad oil of claim 1 in which the base salad oilis derived from hydrogenated soybean oil.

6. The clear glyceride salad oil of claim 1 in which the mixedpolysaccharide ester is present in an amount of from about 0.05% toabout 0.1%, by weight.

7. A clear glyceride salad oil having improved resistance to depositionof high-melting solids and comprising a base salad oil having dissolvedtherein about 0.1% sucrose completely esterified with oleic acid dimerand palmitic acid in a ratio of about 1: 1.

8. A clear glyceride salad oil having improved resistance to depositionof high-melting solids and comprising a base salad oil having dissolvedtherein from about 0.001% to about 1%, by weight, of a mixedpolysacchan'de ester of long-chain unsaturated fatty acid dimer havingfrom about 28 to about 44 carbon atoms in the dimer and long-chainsaturated fatty acids having from about 14 to about 22 carbon atoms,said polysaccharide having from about 2 to about 15 saccharide units permolecule and being at least one-half esterified, and said unsaturatedfatty acid dimer and saturated fatty acid being in a ratio of from about1:6 to about 6: 1.

9. A clear glyceride salad oil having improved resistance to depositionof high-melting solids and comprising a base salad oil having dissolvedtherein about 0.1% sucrose completely esterified with long-chainunsaturated fatty acid dimer having from about 28 to about 44 carbonatoms in the dimer and long-chain saturated fatty acids having fromabout 14 to about 22 carbon atoms in a ratio of about 1:1.

References Cited UNITED STATES PATENTS 2,266,591 12/1941 Eckey et a1.99-163 2,607,695 8/1952 Ayers et a1. 99-163 3,158,489 11/1964 Bauer eta1. 99-118 3,158,490 ll/1964 Bauer et al 99118 A. LOUIS MONACELL,Primary Examiner. MAURICE W. GREENSTEIN, Examiner.

8. A CLEAR GLYCERIDE SALAD OIL HAVING IMPROVED RESISTANCE TO DEPOSITIONOF HIGH-MELTING SOLIDS AND COMPRISING A BASE SALAD OIL HAVING DISSOLVEDTHEREIN FROM ABOUT 0.001% TO ABOUT 1%, BY WEIGHT, OF A MIXEDPOLYSACCHARIDE ESTER OF LONG-CHAIN UNSATURATED FATTY ACID DIMER HAVINGFROM ABOUT 28 TO ABOUT 44 CARBON ATOMS IN THE DIMER AND LONG-CHAINSATURATED FATTY ACIDS HAVING FROM ABOUT 14 TO ABOUT 22 CARBON ATOMS,SAID POLYSACCHARIDE HAVING FROM ABOUT 2 TO ABOUT 15 SACCHARIDE UNITS PERMOLECULE AND BEING AT LEAST ONE-HALF ESTERIFIED, AND SAID UNSATURATEDFATTY ACID DIMER AND SATURATED FATTY ACID BEING IN A RATIO OF FROM ABOUT1:6 TO ABOUT 6:1.